1. Field of the Invention
The invention relates to a data communication apparatus having a communication function of both of voice data and image data.
2. Related Background Art
Generally, in an image communication telephone having a communicating function of both of a voice and an image, the transmission side respectively encodes the voice signal and image signal, multiplexes the resultant codes and transmits to the partner side. The reception side separates the multiplexed codes, decodes each code and generates the voice and image. In the case of displaying the image, there is known what is called a picture in picture (PinP) function to not only display the image on the partner side but also display both of the image on the partner side and the own image by a multi-window.
Hitherto, such a kind of image communication telephone is constructed so as to switch an image plane in a mode to display only-the image on the partner side and an image plane in the PinP mode by a switching operation. Therefore, by selecting the image plane in the PinP mode by the switching operation, the user can display the own image which is displayed in the image communication telephone on the partner side.
However, in the above conventional image communication telephone, since the image plane in the PinP mode is manually switched, for instance, in the case of checking the own image before the start of the communication, the switching operation must be performed each time, so that there is a problem such that the operation is troublesome.
On the other hand, according to the apparatus such that an image communication telephone having a data communicating function of a voice and an image is provided with an application function such as function of a word processor (typewriter), function of a computer, or the like, when a call reception occurs during the display of an image plane of the application function and a handset is off hooked, the image plane is automatically switched to the image on the partner side.
In the above conventional image communication telephone, however, in the case where the image plane of the application function is displayed by a display unit, when a call reception occurs and the handset is off hooked, the image plane is automatically switched to the image on the partner side. Therefore, the image plane is switched even in the case where the user doesn't erase the image plane of the application function or the partner side doesn't transmit the image, so that there is a problem such that it is troublesome for the user.